Flame retardant (FR) materials control or reduce the risk of fire and therefore have a direct impact on safety. Flame-retardant additives are often needed as a component of finished commercial products and, more specifically organic/polymer based materials. Approximately 909,000 tons/year of flame retardant additives are used in the polymer industry alone to make them less flammable.
Flame initiation and subsequent propagation through a material can happen in several different ways. Propagation of flame through the polymer backbone is often preceded by the formation of extremely reactive OH and H radicals. Most halogenated FRs act by the abstraction of these highly reactive radicals. Other flame retardants, including some metal oxides, work on the principle of generating char, forming a protective layer on the surface, which starves oxygen supply to the interior layer, facilitating flame quenching. The use of halogenated flame retardants is convenient and popular because of its good compatibility with polymer systems, easy processability and very efficient fire retardancy.
In the polymer industry, flame retardancy is often achieved by blending polymers with flame retardant additives, such as halocarbons, including polybrominated diphenyl ether (PBDE), phosphorous, organophosphates and metal oxides. While small molecule flame-retardant additives provide a convenient means for reducing flammability of materials, these additives may compromise safety from environmental and health perspectives. Conventional FRs are small molecule additives that often leach out of the polymer during their use leading to a variety of serious health and environmental problems associated with toxicity and bioaccumulation. Halogenated compounds are linked to detrimental effects on the nervous system. The presence of trace amounts of PBDEs in sperm whales, seals, dolphins and even the human population, poses enormous environmental threat and health related issues throughout the world. With the European Union banning the use of halogenated FR, there has been a tremendous need for the development of environmentally friendly, non toxic, low leaching alternative halogen free FR polymers and additives.